| 摘要 |
A metal perforating stencil for use in making perforations in a film under vacuum comprises a metal support in which there are continuous openings which are separated by dykes. In this stencil, the ratio of the thickness of the stencil with respect to the maximum radius of an opening on the active side of the stencil is greater than 1.15. If desired, at least the active side of the stencil may be provided with a rough surface structure which is deposited by electrodeposition means. A stencil of this type has improved release properties, resulting in a long service life, which also has a beneficial effect on the production rate and the quality of the perforated film which is obtained using the stencil. |
